Employee Benefit Plans - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares
Number of Shares
Outstanding, vested and expected to vest, Beginning balance | shares	15,100,142
Granted | shares	2,904,930
Exercised | shares	(1,543,809)
Forfeited | shares	(1,133,816)
Expired | shares	(106,057)
Outstanding, vested and expected to vest, Ending balance | shares	15,221,390	15,100,142
Vested and exercisable at September 30, 2021 | shares	10,986,983
Weighted Average Exercise Price
Outstanding, vested and expected to vest, Beginning balance | $ / shares	$ 16.07
Granted | $ / shares	21.61
Exercised | $ / shares	13.95
Forfeited | $ / shares	19.59
Expired | $ / shares	19.35
Outstanding, vested and expected to vest, Ending balance | $ / shares	17.06	$ 16.07
Vested and exercisable at September 30, 2021 | $ / shares	$ 15.92
Outstanding, vested and expected to vest, Aggregate Intrinsic Value, Beginning balance | $	$ 143,156
Outstanding, vested and expected to vest, Aggregate Intrinsic Value, Ending balance | $	47,918	$ 143,156
Vested and exercisable at September 30, 2021 | $	$ 43,565
Outstanding, vested and expected to vest, Weighted Average Remaining Contractual Term	6 years 6 months	6 years 10 months 24 days
Vested and exercisable, Weighted Average Remaining Contractual Term	5 years 7 months 6 days